The Financial Times report states that as of April 2019, Amazon boasted more than 32 million subscribers worldwide across all of its music services, which include Prime Music (included with every Amazon Prime subscription) and the more-expansive Prime Music Unlimited (which costs $7.99/month for Prime members and $9.99/month for non-Prime members). The Music Unlimited tier also includes the low-cost Echo Plan, which costs $4.99/month to stream on a single Echo device or Fire TV, as well as a discount Unlimited plan for college students, also priced at $4.99 monthly.
The caveat here is whether Prime Music members -- who are automatically subscribed upon signing up for a regular Prime membership -- can really be counted as subscribers given that they don’t opt in to Prime Music specifically. A MusicWatch report released last September, for example, did not include Prime Music members in its overall tally of paid music streaming subscribers in the U.S.
When looking at the overall number of Prime subscribers -- which topped 100 million in April 2018, according to Amazon -- the 32 million number also doesn’t add up if it is indeed meant to tally subscribers across all of Amazon’s music services. It’s additionally unclear whether every individual included in Amazon Music’s family plans is counted as part of the tally, as is the case with other streamers including Spotify and Apple.
When reached for comment, an Amazon representative told Billboard that the 32 million number cited by FT is "speculative." They noted that the company has not publicly announced any subscriber numbers for its music services.
In an April 2018 interview with Billboard, Amazon Music vp (now head) Steve Boom said the growth of Amazon's music services could be attributed to both the expanding number of Amazon Prime members and the popularity of the company's voice-activated Echo devices. At the time, Boom said Amazon Music had "tens of millions" of paid subscribers.
Boom has additionally claimed that the Amazon Music services' subscriber base skews significantly older than it does for Spotify and Apple, telling FT that 14% of Music Prime subscribers are aged 55 and older (as compared with around 5% of Spotify subscribers and only a slightly higher percentage of Apple Music subscribers, according to MIDiA research data cited by FT).
Spotify is currently the music streaming leader with over 100 million subscribers globally, followed by Apple Music at 60 million -- though the latter recently surpassed Spotify’s subscriber count in the U.S.
Though Amazon still lags far behind its top two rivals, it has been making major moves in the music streaming space as of late. Most recently, the company was reported to be developing a high-definition music service that could launch by year's end.